code: def __init__(self, dim_in, proj_dim=256, proj="convmlp"):
      super(ProjectionHead, self).__init__()
  
      if proj == "linear":
          self.proj = nn.Conv2d(dim_in, proj_dim, kernel_size=1)
      elif proj == "convmlp":
          self.proj = nn.Sequential(
              nn.Conv2d(dim_in, dim_in, kernel_size=1),
              nn.SyncBatchNorm(dim_in),
              nn.ReLU(),
              nn.Conv2d(dim_in, proj_dim, kernel_size=1),
          )
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg.cvlibs import manager, param_init
  from paddleseg.models import layers
label_desc: Use image node_id 1 to create a new ProjectionHead object from inherited base classes: nn with example: obj = ProjectionHead(dim_in, proj_dim, proj)